A conventional gas insulating apparatus, for example, as disclosed in Japanese Application Patent Laid-Open Publication No. Hei 10-210613, comprises a circuit-breaker unit, a disconnector unit, an instrument current transformer unit, an instrument voltage transformer unit, a lightning-arrester unit and bushings, wherein space between bushings is made small to reduce the size of the apparatus, thereby floor area can be reduced.
Theses days, the demand for a smaller gas insulating apparatus has been increasing. As a solution, it can be expected that devices which constitute a gas insulating apparatus can be integrated. For example, a gas insulating apparatus disclosed in Japanese Application Patent Laid-Open Publication No. Hei 8-275323, contains a circuit-breaker, a disconnector, a grounding switch, a current transformer and a voltage divider in one container, thereby the size of the gas insulating apparatus can be reduced.
However, the above-mentioned method requires the development, design and production of a new device which can contain all devices constituting a gas insulating apparatus and can also satisfy desired design specifications. Accordingly, the cost for the gas insulating apparatus increases. Further, in the above-mentioned method, because locations of a current transformer and a voltage divider are limited to both ends of the circuit-breaker, the protected area of the current transformer and the voltage divider is small. Consequently, for example, a ground fault which has occurred inside the gas insulating apparatus may be determined to have occurred outside the gas insulating apparatus. As a result, the reliability of the gas insulating apparatus is lowered.